Gut Microbiome, Bacteria, and Lupus

The bacteria in the body, particularly in the gastrointestinal tract, have a major impact on health and lupus. When it comes to gut health, it’s all about finding the right balance.

From interfering with the stomach and intestines to causing inflammation in the liver, lupus can cause a range of gut health problems. But, recent studies have also found that the bacteria in the gastrointestinal tract can alter lupus symptoms

What is the Gut Microbiome?

Usually, when you think of bacteria, you think of the ones that make you sick. When bacteria infect our bodies, they can cause diseases like pneumonia, meningitis, strep throat, and food poisoning. But, we also live peacefully with bacteria in our bodies that help us live healthy lives.

About 10-100 trillion bacteria live on our skin, in our mouths, and in the gastrointestinal tract. The bacteria in our gut help:

break down food

produce essential vitamins

regulate metabolism and immune system

influence how we think

These “good” bacteria may even keep the infectious bacteria from causing damage. Scientists continue to discover new ways that these bacteria help the human body. The bacteria within us is comprised of hundreds of species, and each person’s collection of gut bacteria is as unique as a fingerprint.

These colonies of bacteria are called the “microbiome.” (Biome is another name for an ecosystem). Genetics, diet, and geographic locations all impact the bacteria present in the microbiome. Scientists are finding that different balances of gut bacteria are linked to conditions including obesity, diabetes, and autoimmune diseases, including lupus.

Lupus and the Gut Microbiome

There are two hypothesized ways that the microbiome may be impacted by lupus according to research:

Inflammation from lupus causes damage to the gut wall and disrupts the bacteria that is present. These changes modulate the immune system and may lead to more lupus damage

Lupus causes autoimmune damage to the gut wall and then directly attacks the bacteria that live in it. Normally, the immune system does not attack the “good” bacteria in the gut, but, when the wall is damaged, the bacteria are no longer protected. When it attacks the bacteria, lupus causes the imbalance in the microbiome, and disrupts the normal functions of the body that use the bacteria.

It may also be a combination of both. In the end, the damaged gut wall and the imbalanced microbiome cause fragments of bacteria and the proteins that can cross over into the bloodstream. The immune system attacks these pieces, causing inflammation throughout the body.

Instead of being a cause of lupus, most researchers think of the microbiome as a feedback loop, that changes over the course of the disease and either ramp up or ramp down the symptoms.

In the study, which was funded by the Lupus Research Alliance, 61 women with SLE and 17 health women donated blood and fecal (poop) samples to be studied. The researchers were trying to find a link between the immune system antibodies in the blood samples and the bacteria RNA – an alternative to DNA that many bacteria use – in the fecal smaples. RNA sampling of fecal samples is a reliable method for seeing what bacteria are in the person’s body.

When they analyzed the samples, the researchers found that women with SLE had 5-times higher levels of a bacteria called Ruminococcus gnavus. This bacteria is otherwise harmless, so it wasn’t causing an infection and it wouldn’t be able to make the people sick on its own.

However, because of damage to the gut wall, pieces of the bacteria and proteins that it created were entering their bloodstreams. Antibodies to R. gnavus were found in their blood samples, which meant that their immune systems were attacking these pieces. Although there was no threat, their immune systems – already hyper-reactive to threats – was causing inflammation and increasing its ferocity throughout the entire body, increasing lupus symptoms as it caused more damage.

Interestingly, a different bacteria called Bacteroides uniformis was found at 4-times lower levels in the women with lupus. B. Uniformis is also harmless, but it competes with R.gnavus and helps to keep the other bacteria’s numbers in balance. Though this study was done in women only, the researchers found that similar ratios of these two bacteria showed up in a small group of men with lupus as well.

This study, and others like it, strongly suggest that changes to the gut microbiome can help with both symptoms and overall disease activity. One study in mouse models found that changing the gut microbiome mice with lupus nephritis helped reduce their symptoms.

Taking Care of the Gut Microbiome

Bolstering the gut microbiome can be as easy as changing what you put into your body.

Fiber is well known to promote gut and microbiome health, so changing your diet to a high-fiber, low carbohydrate diet is a great way to make sure that certain good bacteria species are fed. You can read more about high fiber diets and lupus here.

Taking in plenty of vitamin B, vitamin A, and Omega 3 fatty acids will also help. If your diet doesn’t have enough of it, supplements may help.

Probiotic pills, or natural probiotics such as yogurt, miso, and other fermented foods, take a different route to improving gut health. Instead of feeding the bacteria already in your body, they bring in fresh recruits from outside. Studies in mice show bringing in new bacteria can help restore the balance in the gut and improve lupus symptoms. You can read more about probiotics here.

You should also be careful of antibiotics – while they keep you safe from infection, they don’t just kill the bacteria making you sick. A course of antibiotics can tear through your gut flora and unbalance your microbiome. If you have questions, be sure to bring them up with your lupus treatment team.